No GTA city sets a validity period for an arborist report. The bylaws of Toronto, Mississauga, Markham, Richmond Hill and Brampton contain none, and neither do Toronto’s report guidelines. What the cities do set is the life of the permit or application: Richmond Hill permits expire 12 months after issue (extendable to two years), Mississauga treats an application as withdrawn after two years, and Toronto’s General Manager sets expiry dates by permit or application. The 12-month figure many consultants use is industry practice, not a municipal rule. Mississauga’s terms of reference treat survey base information as valid for one year or until the site changes, and Vaughan’s protocol requires inventory field data to be no more than three years old. Beyond that, report age is a matter of reviewer practice, counted from the date of the site inspection.
A homeowner who commissioned a report last spring, waited through winter, and is now filing a permit application in May is submitting a document close to a year old. A builder who revised a development plan after the arborist report was written is filing documentation that no longer reflects the site. In both cases, expect the city to ask for a new inspection before it processes the application.
Report Age Runs From the Site Inspection
The date on the cover page of an arborist report is the date the report was signed, which can differ from the date the arborist visited the property. Those can be days or weeks apart. A reviewer looks at the inspection date, because that is when the arborist documented the tree’s condition.
If you’re not sure which date applies, look for the site visit date in the report’s body or methodology section. That’s the date reviewers count age from.
What Makes a Report Obsolete
Four things make an existing report obsolete, whatever its age.
If the tree’s condition changed, the report needs updating. Trees decline faster than they improve. A tree that was in fair condition in June may be structurally compromised by the following spring after a hard winter and ice loading. If the condition rating in the existing report no longer matches what an arborist would observe today, the report needs updating.
Construction activity occurred near the root zone. Ground disturbance, excavation within the drip line, or new utility trenching can materially change a tree’s condition. City reviewers ask whether any site activity has occurred since the inspection date. If it has, and the report predates it, you need a supplementary inspection.
The scope changed. If additional trees are now part of the removal application, or if the original application was for removal but the current one involves construction impact, the existing report doesn’t cover the expanded scope.
The plan revisions changed which trees are affected. Development and renovation plans get revised. When a revised site plan places a structure, driveway, or utility closer to a tree that wasn’t previously in the impact zone, the arborist report needs to reflect the new conditions. Submitting an outdated report alongside a revised plan will generate a request for information from city staff.
Revision vs. a New Report
Not every change requires a brand-new report and a new site visit. The distinction depends on whether the underlying inspection data is still accurate.
A revision is appropriate when the inspection data remains valid but the report needs to be updated to reflect new conditions on paper. Examples include a change in the proposed removal timeline, a minor plan revision that doesn’t affect tree locations, or a correction to a replanting plan based on feedback from city reviewers. The arborist can update the document without returning to the site.
A new report is required when the inspection itself is outdated. That means the arborist needs to return to the property, conduct a fresh assessment, and document current conditions. Age, scope changes and post-inspection site activity are the usual reasons.
If the inspection data is out of date, order a new report. A revision submitted when the city needs a new inspection adds a round trip with city staff and weeks to your timeline.
Why Report Age Matters When You File
The municipal review period does not include the time needed to commission the report, schedule the site visit, and complete the documents.
If your report was written 9 months ago, it will be close to a year old before the city finishes its review. No bylaw sets a cutoff, and reviewers won’t hold a report to an exact day. In practice, though, a report that’s visibly stale, or where the inspection date was close to a year ago at submission, can attract additional scrutiny or a request for confirmation that conditions haven’t changed.
Time the inspection and report for when you are ready to file. If you know the permit application will go in within a few weeks of the report being delivered, report age isn’t a concern. If there’s a long gap between the report and the intended application, either plan the inspection closer to the filing date or build an allowance for a supplementary review into your timeline.
A Construction Report Must Match the Site Before Ground Is Broken
For construction-related tree reports, the validity question is tied more tightly to the active project than to a calendar year. A construction report documents existing tree conditions at the start of a project and sets protection measures for the trees staying on site. That report needs to reflect conditions before ground is broken.
If a construction project is phased over multiple years, or has been dormant and is restarting, city reviewers check that the original construction report still matches the site. City reviewers assessing an active building permit will want to confirm that the tree assessment still reflects what’s actually on the site. Toronto does not require a post-construction report as a standard condition: the owner notifies the local Tree Protection and Plan Review office at the end of construction with photos. Markham may require a Tree Impact Report or a Certificate of Completion from a Qualified Tree Expert, and inspects one month after building completion.
Order the Report Close to Your Filing Date
Toronto staff review the package as filed and list the missing items in writing. Review picks up again once those items arrive. A report that does not match the current plans leaves a package incomplete and costs a round of comments.
If you’re planning a tree removal or a construction project that involves protected trees, commission the report close to your intended application date. If your timeline slips after the report is in hand, check the inspection date before you file. See which arborist report applies to your project before you commission one.
Our team prepares tree removal permit reports for homeowners and builders across the GTA, written to each municipality’s current standards. We’ll also tell you plainly whether an existing report can be revised or whether a new inspection is the right call.